Thread-treating composition



Patented Sept. 22, 1936 UNITED. STATES THREAD-TREATING COMPOSITIONAlexander B. Mould, Yonkers, N. I as- Blscklng & Chemical 00..

slg'nor to Boston- Boston, Mara, a corporation of No Drawing.Application SerlaiNo. exam 1 12 Claims.

This invention relates to improvements in materials commonlyspoken of aswax", for treating the thread used in the sewing together of shoe parts.The invention is disclosed herein as u embodied in compositions of thetype known as hot waxes whichareapplied to the thread in moltencondition immediately prior to the employment .of the thread in a sewingoperation.

An important application of such hot waxes is in the wetting orinseaming operation, in the performance of which a chain stitch sewingmachine is used to sew a welt and a shoe upper to the lip or rib of aninsole to which the upper has been lasted. The invention, therefore,will be disclosed a in connection with the performance of thisoperation, although it will be understood that it may be employed inconnection with other sewing op-. erations.

For the welting or inseaming operation the type of sewing machineforming a chain stitch is generally used. As is well known, however,chain stitch seams will ravel unless the last stitch is securely set inplace and, furthermore, it is believed that tighter seams may beobtained, at least in sewing leather and the like, if each-stitch issecurely held in place after the loop has been carried forward to setthe stitch and while the tension on the thread is temporarily releasedat the start of the forward movement of the needle through the work toreceive the thread with which the next loop is formed.

In the manufacture of Goodyear welt shoes it is highly desirable thatthe seam formed in the welting operation be tight in order that thethread of the seam may be invisible from the outside of the finishedshoe and that the joint or crease between the upper and the welt may betight and water resistant. Tightness and uniformity of this welt seam,commonly known as the inseam, is further desirable since this seamserves as a guide in several subsequent manufacturing operations, forexample, welt butting, sole rounding, etc.

In the welt butting operation the ends of the welt are cut oil andskived with the possibility of cutting the stitches adjacent to each ofthe ends of the welt seam. It is very desirable, therefore, that suchstitches be firmly sealed in in order that the ends of the weltmay notbecome loosened from the upper. Tightness of the welt stitches isadditionally desirable for the welt butting operation since the stitchesserve as a guide in this operation.

From an operating standpoint it has been found that a hot wax"composition for treating sewing thread used in the welting operationshould 5 not granulate or crystallize upon standing, since the threadtreating composition in this condition is dimcult to melt and to applyuniformly to the thread. Granulation" of hot waxes made from a rosinbase is believed to be due to the crystallization of the abietic acid ofwhich rosin consists in large part. It is frequently desirable also thatthe wax composition melt fairly readily in order that the sewing machinemay be ready for use reasonably soon after the wax composition is placedin the wax pot.

In order to facilitate the sewing operation the composition in moltencondition should impart slip to the thread so as to facilitate thepassage thereof through the sewing machine and through the leather orother material being sewn andto avoid breakage of the thread which ismaintained under tension. 0n the other hand, in order to obtain a seamof the desired tightness, the wax composition, while in partially moltencondition, should be suiilciently tacky to prevent slipping of theindividual stitch loops upon each other. That is to say, during thecycle of machine operations of forming each stitch there is a period,after each loop is carried forward to set the preceding stitch and asthe needle starts on its forward movement, when the tension on thethread is temporarily released, and the composition on the thread shouldbe sufficiently tacky to prevent slippage of the next previous loop atthis time. -In other words, the coating on the thread while moltenshould facilitate, rather than ofler resistance to, the passage of thethread through the leather or other work, while at the same time thecoating should be somewhat tacky when brought into contact with anotherportion of the coated thread.

The hot wax composition, furthermore, should harden or set fairlyrapidly after the seam has In the operation known as welt beati the weltand adjacent parts are subjected to a continuous hammering action toshape the welt for outsole attaching. It is desirable that the waxcomposition which has been applied to the thread remain sufiicientlyflexible and non-friable after solidification or hardening so as not tobe removed in any substantial quantities during this operation andthereby be prevented from maintaining its protective action upon thethread.

In view of the foregoing it is an object of the invention to provide animproved thread treating composition embodying the desiredcharacteristics hereinabove suggested, and preferably composed ofingredients which in the aggregate are relatively inexpensive.

As illustrated herein, this and other objects are accomplished by athread treating composition consisting predominantly of rosin which issoftened and plasticized with certain advantageous ingredients, forexample, petrolatum and paraffin oil employed in the approximateproportions of 8 parts petrolatum to 5 parts paraffin oil. Thecomposition, furthermore, contains a small amount of rubber, usually afraction of 1%, which has a remarkable effect in preventing or retardinggranulation of the composition, as well as greatly increasing theflexibility, and'substantially decreasing the friability, of thecomposition when it is in solidified form. A unique and highlyadvantageous feature of the composition in its preferred form is thepresence of water therein, say 10%, as the dispersed phase of anemulsion, the preparation of which is assisted by the use of anemulsifying agent such as triethanolamine, theentire composition,therefore, constituting an emulsion of the water-in-oil yp An example ofa hot wax thread treating composition of a yellowor golden color made inPercent Gum rosin (Grade H) 85. 2' Yellow petrolatum (softening point 44C.) 7. '7 Paraffin oil (specific gravity 0.89) 4.8 Pine tar 1. 9 Whitecrepe rubber 0. 1 Triethanolamine (commercial) 0.3

Water about 10% of theabove This composition may be prepared by chargingthe rosin, petrolatum, paraffin oil and pine tar into a steam heatedkettle. Agitation of the mass is preferably commenced as soon aspossible. When the rosin is melted the steam is turned off and therubber added. The rubber is preferably added in the form of a solutioncomprising about 1 part by weight of rubber, 1v part rosin, and '7 partsparafiln'oil. It may be noted that paramn oil and rosin are compatiblewith, and are softeners for, rubber, the paraffin oil servingadditionally to reduce the viscosity of the rubber and to make therubber solution readily pourable. This rubber solution may be preparedin advance and the amounts of rosin and parafiin oil employed may bededucted from the charge to the steam jacketed kettle. After the rubbersolution has been added the agitation is continued and water added,preferably to the extent of about 5 or 6% of the weight of thecomposition in the kettle. At the time of the addition of the water, thetemperature of the material-in the kettle should softness.

not be over 212 F. and preferably is within the range of 200-212 F.Triethanolamine is preferably dissolved in the first portion of wateradded whereby the emulsifieation of the water in the composition ishastened. The composition may then be withdrawn from the kettle andtransferred-to any suitable receiving means, such as a moving belt,where water is sprayed on the composition, thereby coolingthecomposition and at the same time increasing. the water contentthereof to about 10%. The cooled composition is then preferably pulledon a candy puller, as a result of which the color of the composition issomewhat lightened and a wax-likev consistency imparted thereto, afterwhich the composition may be cut and packed.

Just prior to the removal of the composition from the kettle, thecomposition may be tested to determine its degree of hardness orsoftness, or temper, as by a method to be described hereinafter. Thecomposition cited above gives a temper of about 225 seconds. The exacttemper of a composition may vary somewhat due to variability in the rawmaterials, and to assure the production of a uniform product it issometimes desirable to withhold a portion of the petrolatum and paraffinoil until the testing of the temper, and then to add sufiicient of theseingredients to give the desired predetermined temper.

The rosin, of which the above composition consists chiefly, serves togive the composition the desired body and consistency together with thedesired tackiness. It further imparts setting or hardening qualities,that is to say, it makes the composition solid when it cools off fromthe heated condition in which it is applied to the thread. The type ofrosin given in the above specific example refers to the standards of theU. S. Department of Agriculture wherein rosin is graded by color. It maybe noted that rosins of the various color grades vary somewhat ingranulation of the composition, a portion of the rosin may be replacedwith coumaron resin. Gum rosin is the natural resin of Southern whitepine, but in so far as other natural resins of coniferous trees, andindeed synthetic resins, are the equivalents of rosin, I desire the termrosin as employed in the specification and claims to be construed tocover such equivalents.

It may be noted that wood rosin, which is made from tree stumps, has notbeen found satisfactory because of its extreme tendency to granulate. v

The petrolatum, which consists chiefly of petroleum hydrocarbons, servesto plasticize the rosin to some extent and to give the desired slip orlubricating quality to the composition so that the treated thread may bepulled readily through the sewing machine and through the material beingsewed while the composition thereon is in molten condition. Theliability to thread break-' age is thus substantially eliminated. Thepetrolatum may be of yellow or white color varying ordinarily insoftening point from 28 to 42 0., the color of the petrolatum employeddepending partly on the color desired in the final composition. The termpetrolatum as employed in the The use of paramn oil, therefore, preventsthe In order further to assist in retardingcondition known as "drythread" in which all of the composition is on the outside of the thread,and'by imparting the penetrating quality, provides adesired gutty"characteristic to the thread. Additionally, the paraflin oil impartssome lubricating qualities to the composition but apparently not to thesame extent as does the petrolatum. The parafllp oil preferably has aspecific gravity in the neighborhood of 0.89, a

portion of 8 to 5. The use of petrolatum and paraflin oil inapproximately this proportion I havev found to be particularly useful inmy thread treating composition in that thereby the composition may besoftened readily without, on the other hand, impairing the quick-settingcharacteristics thereof.

The pine tar in the above composition serves primarily to impartadesired golden color thereto.

The rubber in my improved composition serves as an inhibitor ofgranulation, and as a promoter of flexibility of the solidifiedcomposition. Since granulation is believed to be the crystallization ofthe abietic acidvof which rosin consists in large part, as statedhereinabove, a function of the rubber may be considered to be thepreven- .tion of the crystallization of the abietic'acid.

In performing this function it appears likely that the rubber sets up ajell structure which slows up the forces-of crystallization. While Ihave found a content of about 0.1% of rubber. as in the above specificexample, to be sufficient to produce the desired result,- I haveemployed up to about 1% of rubber with satisfactory results.

White crepe rubber is preferred for the rubber ingredient because itgives the lightest color. Moreover, white crepe rubber is softened byparaflin oil and rosin somewhat more readily than are other commercialforms of rubber, for example, smoked sheet or Para rubber, and istherefore highly suitable for the preparation of the rubber solution orsuspension in which form the rubber is preferably introduced into thethread-treating composition as described hereinbefore. Generallyspeaking, any form of rubber may be employed which is compatible withpetrolatum and paraffin oil.

The triethanolamine, which is a mild organic alkali and which I preferto employ in my improved composition, acts as a peptizing agent and aidsin the emulsiflcation of the added water to form an emulsion of thewater-in-oil type in which the water constitutes the dispersed phase.

The triethanolamine additionally is believed to improve the lubricationof the thread ,by the composition so as to increase the slip or abilityof the thread to pass readily through the sewing machine and through thematerial being sewn. When a bleaching agent is added to the composition,as in the formation of white waxes, the triethanolamine servesadditionally to neutralize any excess of free mineral acid from thesodium bisulphite or other bleach. While I prefer to incorporatetriethanolamine into my improved composition, in certain cases otheralkalis or emulsifying agents may be employed, for example, sodiumhydroxide, or the emulsifying agent may be omitted entirely while stillretaining many of the advantages of my invention, although wherepossiblethe use of an emulsifying agent is preferable.

The presence of water in emulsified form in the composition appears toimprove the action on the thread, particularly on linen thread. A threadwetted by the small amount of water present in my improved compositionappears to work better than a stiff dry thread. The water, it will benoted, is present as the dispersed phase of' a water-in-oil type ofemulsion, the rosin, paraflin oil, petrolatum and rubber serving as thecontinuous phase of the emulsion. The water in this dispersed,emulsified form is thus distributed very uniformly throughout the waxcomposition whereby a uniform action upon the thread is obtained and,moreover,-the water in this form is not fugitive, that is to say, is notreadily removed from the composition upon standing. Thus, while thewater may in certain instances be omitted, in which case thetriethanolamine may also be omitted, its presence particularly inemulsified form performs a highly advantageous function.

position should melt reasonably rapidly in the wax pot on the sewingmachine and should not drip oi! the thread or machine during a sewingoperation. The degree of hardness or softness of the wax compositionimparting these and other characteristics is termed temper. I have foundit convenient to determine and control the temperof the wax compositionby a float test apparatus such as employed by the American Society forTesting Materials for determining the consistency of bituminousmaterials (see A. S. T. M. Standards for 1927, N0. Dl39-2'7; Bulletin1216 of the U. S. Department of Agriculture, page 55; and the Journal ofIndustrial and Engineering Chemistry, vol. 10, N0. 10, page 818, October1918).

' The apparatus err. ployed in this test comprises an aluminum float anda brass collar into which the sample to be tested is placed. The centralaperture in the collar is filled with the wax composition to be testedand brought to a temperature of about 5 C. after which the collar isattached to the float which is then placed in a relatively large body ofwater maintained at 60 C. When the wax is sufliciently softened by thewater to permit the water to enter into the collar and the float, thefloat sinks. The time elapsed in seconds from the placing of theapparatus on the water until thewater breaks through the wax is ameasure of the consistency of the material under examination. Thecomposition cited in the above specific example gave a float test ofabout 225 seconds. This consistency of composition is suitable foraverage temperature conditions and is commercially known as being ofspring or fall temper.

In some factories a somewhat harder wax commaintaining the proportionof. petrolatum to paraffln oil of about 8 to 5. Examples of suchvariations of the above specified composition on the dry basis forwinter and summer temper are as follows:

In the above cases water is added to the extent of about 10% of the dryweight as in the firstmentioned specific example.

In general it may be said that compositions according to my inventionmay range in temper from about 175 to 300 seconds according to theparticular use to which the composition is put, and indeed in someinstances the temper may vary somewhat without these limits.

In certain cases a wax is desired which is substantially white in color.Such a composition may be obtained by omitting the pine tar mentioned inthe hereinbefore-described compositions and by employing a lightercolored rosin and white petrolatum and by introducing a bleach. Anexample of a white wax composition of 225 seconds temper made accordingto my invention is given below, the percentages by weight being on thedry basis:

' Per cent Rosin (Grade WW) 87.8 White petrolatum (softening point 42'C.) 7.1 Parafiln oil (specific gravity 0.89) 4.4 White crepe rubber 0.1Triethanolamine 0.3 Bisulphite of soda (technical) 0.3

In the above case it may be noted that the triethanolamine also performsthe function of neutralizing any free mineral acid present due to theuse of the bisulphite of soda bleach. In the preparation of the abovecomposition the bleach is preferably added to the compositionsufliciently early to permit the bleaching action to take place beforethe removal of. the composition from the kettle. The rubber solution ispreferably added shortly prior to the removal of the composition fromthe kettle, the remainderof the preparation being the same ashereinabove described with reference to the first example; Theproportions of rosin, petrolatum and paraflin oil may be varied toproduce softer and harder compositions in the manner indicated abovewith respect to the yellow or golden wax first hereinabove described.

While I have described certain specific compositions the ingredients maybe varied within reasonably wide limits to produce compositions comingwithin the scope of my invention and having many of the desirablecharacteristics contemplated by this invention. Chemical equivalents ofthe specific substances herein disclosed may be employed and the claimsshould be construed to cover such equivalents. Furthermore, additiona1substances may in certain cases be added to the wax composition toobtain modified characteristics while still remaining within the scopeof this invention. The proportions may of course be varied somewhatdepending upon the particular grades and characteristics of rosin,petrolatum. and parafiin oil employed. By way of example,. theproportions of various ingredients herein disclosed may vary within thelimits approximately as set forth hereinbelow to provide compositionshaving tempers from about 175 to 300 seconds.

- Per cent Rosin to Petrolatum 3 to 15 Paraffin oil 1 to 10 Rubber 0.1to 1 Pine tar '3 to 3 Bleach (sodium bisulphite); 0 to 1 Emulsifyingagent (triethanolamine)- 0 to 1 Water 5 to 15% of the above Havingdescribed my invention, what I claim as new and desire to secure byLetters Patent of the United States is:

1. The method of treating sewing thread which comprises applying to saidthread a molten composition containing approximately 75 to 95% rosin,and small amounts of petrolatum, paraflin oil, rubber and water.

2. A thread treating composition of the hot wax type adapted to bemelted and applied while in molten condition to a thread, saidcomposition comprising an emulsion of the water-in-o'il type thecontinuous phase of which contains approximately '75 to 95% rosin andmaterial to plasticize said rosin, and the dispersed phase of whichcomprises water.

3. A thread treating composition of the hot wax type adapted to bemelted and applied while in molten condition to a thread, saidcomposition comprising an emulsion of the water-in-oil type thecontinuous phase of which comprises approximately 75 to 95% rosin, 3 to15% petrolatum, and sufiicient paraffin oil so that the ratio ofpetrolatum to paraflin oil is about 8 to 5 by weight, and the dispersedphase of which comprises water.

4. A thread treating composition of the hot wax type adapted to bemelted and applied while in molten condition to a thread, saidcomposition comprising an emulsion of the water-in-oil type thecontinuous phase of which comprises approximately 75 to 95% rosin,material to plasticize said rosin, and 0.1 to 1% rubber, and thedispersed phase of which comprises water.

5. A thread treating composition of the hot wax type adapted to bemelted and applied while in molten condition to a thread, saidcomposition comprising an emulsion of the water-in-oil type thecontinuous phase of which comprises approximately '75 to 95% rosin,petrolatum, paraffin oil, and rubber, and the dispersed phase of whichcomprises water.

6. A thread treating composition of the hot wax type adapted to bemelted and applied while in molten condition to a thread, saidcomposition comprising rosin in amount of about '75 to 95%, about 3 to15% petrolatum, and sufiicient paraflin oil so that the ratio ofpetrolatum to paraffin oil is about 8 to 5 by weight, said percentagesbeing calculated on the dry basis.

7. A thread treating composition of the hot wax type adapted to bemelted and applied'while in molten condition to a thread, saidcomposition comprising rosin in amount of about '75 to 95%,

material to plasticize said rosin, and about 0.1 to

1%. rubber, said percentages being calculated on the dry basis.

8. A thread treating composition comprising about '75 to 95% rosin,about 3 to 15% petrolatum,

suflicient paraffin oil so that the ratio of petrolatum to paraffin oilis about 8 to 5 by weight, and about 0.1 to 1% rubber, said percentagesbeing calculated on the dry basis.

9. A thread treating composition having a temper of from 175 to 300seconds and comprising about to 95% rosin, about 3 to 15% petrolatum,sufficient paraflin oil so that the ratio of petrolatum to paraffin oilis about 8 to 5 by weight, and about 0.1 to 1% rubber, all calculated onthe dry basis, and water in the neighborhood of 5 to 15% of the weightof the abovementioned ingredients.

10. A thread treating composition having a temper of from 200 to 250seconds and comprising about to rosin, about 5 to 12% petrolatum,sufiicient parafiin oil so that the ratio of petrolatum to paraflin oilis about 8 to 5 by weight, and about 0.1 to 1% rubber, all calculated onthe dry basis, and water in the neighborhood of 5 to 15% of the weightof the above-mentioned ingredients.

'11. A composition for treating sewing thread comprising the followingingredients in approximately the following proportions by weight on thedry basis:

Per cent Rosin 75 to Petrolatum 3- to 15 Paraflin oil 1 to 10 Rubber 0.1to 1 and water in the neighborhood of 5 to 15% of the weight of theabove.

12. A composition for treating sewing thread comprising the followingingredients in approximately the following proportions byweight on andwater in the neighborhood of 5 to 15% of the weight of the above.

ALEXANDER n. MACDONALD.

